Background:One of the most serious and lethal type of cancer among women with a high mortality rate is breast cancer.

Methods: Relatively, this study examined the alternations of polymorphism of XRCC1gene in codon of Arg 399 Gln on 150 patients who had breast cancer and 150 normal ones as control cases in ages between 25 to 35 and also 45 to 55 after obtaining patients consent alongside with confirmation of pathology and oncology department in Imam Sajad hospital, Ramsar. Correspondingly, the genetic analysis was accomplished by RFLP-PCR technique and also MSPI restricted enzyme was used in order to find the SNPs.

Results: The measured clinical qualifications of all patients were comprised: SD and Mean of age: 4.8 and 48, SD and Mean of menstrual age: 4.8 and 13, SD and mean of menopause: 4.8,49, SD and mean of height: 12 and 175, SD and mean of weight: 67.2 and 91, SD and mean of children’s numbers: 103 and 3.

The final results have indicated that the polymorphism of XRCC1 gene in 150 patients which had breast cancer, had 76.67% heterozygosity (p= 0.03) and 27.87% homozygosity (p=0.02).